A cyclonic type fuel burner is one in which the combustion materials and air move in a whirling movement during combustion. A particular example of an advanced type of cyclonic fuel burner is that illustrated in the U.S. Pat. to Lutes et al, No. 3,777,678. That patent discloses injecting the combustible materials and air tangentially into a horizontally disposed, circular combustion chamber to impart a whirling movement to the materials and their combustion. An auxiliary burner initiates the combustion, which is then maintained with the pressure, velocity and volume of air being changed along the length of the combustion chamber. This provides optimum flame length and burning of the materials, under relatively static conditions.
Systems utilizing such cyclonic type burners as illustrated in the Lutes et al patent, normally employ a control means for controlling the amount of fuel fed into the combustion chamber. The fuel feed is set by that required to provide the desired temperature of the combustion gases and other air mixed therewith at a point downstream from the burner. While this control system with this type of burner achieves very improved results in burning many types of fuel materials, it is desirable to achieve a more optimum control of the burn process and of the slag resulting from the burning and of the downstream temperatures, than has been possible with the known cyclonic type burners.